Microfeature Fabrication in Brittle Materials Using Rotary Ultrasonic Micro-Machining

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Microfeature fabrication (including micro-drilling, micro-grooving, and micro-texturing) of brittle materials has been used in a variety of applications, such as the micro-drilling of silicon wafers/panels for use in pressure and flow sensors and solar panels, micro-drilling in dentistry and orthopedic surgeries, micro-machining of high-temperature ceramic fuel nozzles for aerospace engines, and micro-featuring of optical components like lenses and fibers. The brittleness of these materials makes them difficult to be machined using conventional mechanical processes, which can cause chipping and fracture. Thermal and chemical non-traditional machining (NTM) processes have also been applied for micro-machining. However, NTM can cause unwanted material oxidation and heat-affected zones, can have poor machining efficiency and can require chemical use. A high-efficiency, cost-effective, and high-quality micro-fabrication process for brittle materials is needed. This award supports fundamental research in microfeature fabrication in brittle materials using rotary ultrasonic micro-machining (RUµM). Many knowledge gaps on the RUµM process prevent its widespread use today. The research will fill some of the knowledge gaps and could have significant impacts on electronic, medical, aerospace, optical device, and other high-tech industries. Research results can help reducing manufacturing cost and eliminate chemical usage, which would benefit the environment, economy, and society in general.The research goal of this project is to generate fundamental understanding of tool and workpiece behavior in rotary ultrasonic micro-machining to enable an effective, efficient, and high-quality microfeature mechanical grinding process for brittle materials. The research objective is to discover the mechanisms of material removal, cutting force generation, and surface formation and quality through the interactions between abrasive and workpiece with the assistance of ultrasonic vibration. The successful completion of this project will specifically generate knowledge on (1) material fracture and removal mechanisms for different tool abrasive geometries under different machining variables, (2) cutting force generation mechanisms through single abrasive particle-workpiece interactions at the microscale with ultrasonic vibration, and (3) surface formation under different ultrasonic vibration conditions and modeling of surfaces which result from the material removal processes. Both undergraduate and graduate students, including those from the underrepresented groups, will be involved in conducting experiments and analyzing results.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.